China's Li Na fought into Canada's Rogers Cup semis after a stellar performance to knock out Slovakia's Dominika Cibulkova 7-6 (1), 6-2.Li defeated world's 20th-ranked Cibulkova with relative ease in their quarterfinals duel at the Rexall Centre in Toronto, with China's only Grand Slam singles winner leading in all four of their head-to-head matches.

Cibulkova, who shocked tennis fans twice at the WTA Premier 5 event when she took out world No. 9 Angelique Kerber in the first round, and No. 10 seed Roberta Vinci in the third, was overpowered and outplayed by Li.

The Chinese player got an early lead on Cibulkova, but lost a bit of steam as she started struggling with her serves, losing points in five double faults, including two in one single game that led to her opponent breaking even at 4-4 in the set.

Despite these unforced errors, Li, runner-up of last year's Rogers Cup, played a strong and steady match against Cibulkova, who whipped the ball with brute force into Li's court the entire way. But the strong baseline player returned the balls with equal force, and eventually won the first set in a tie-break.

"I was feeling a little bit different than yesterday because the opponent hit the ball different, but I was feeling today is even more tired than yesterday," said Li Na, who defeated Serbia' s Ana Ivanovic in a close battle by 3-6, 6-1, 7-6 (5) in the third round. "I don't know, maybe I have a tough match (the) day before."

"Today, I didn't have a lot of winners, but I was checking information and I still have 33," she added. "I thought I still can hit a lot of winners in (the) match."

Li will be facing Romania's Sorana Cirstea in semis, the latter defeat Czech player Petra Kvitova 4-6，7-5，6-2. In another semis, No. 4 Radwanska may have a tough road ahead, as she is set to face world No. 1 Serena Williams. Good luck.